The present invention is in the field of wood restoration, and more particularly is a method for imparting a color change to finished articles of wood or wood-grained materials, and the articles produced thereby.
Wood is typically finished in a process that involves coloring the wood with a stain or dye and then coating the colored wood with a protective sealer. Protective coating compositions that are used to finish articles of wood include linseed oil, mineral oil, tung oil, Danish oil, shellac, lacquer (nitrocellulose or water-based), phenolic-resin varnish (spar varnish), polyurethane varnish, water-based varnish, enamel, and wax. Each composition possesses different characteristics of gloss, quickness of drying, resistance to heat, water, alcohol, and other chemicals, ease of application and clean-up, and compatibility with other finishes. In addition, each reacts differently to hardwood and softwood as well as to the characteristics of individual articles of wood.
Nitrocellulose is strongly preferred by professional finishers and furniture factories as the protective coating for wood articles. In fact, most furniture currently manufactured commercially has a nitrocellulose top coating. Nitrocellulose is a strong, clear, quick-drying finish in both its sprayed and brushed form. It is quite durable, and can be polished to a high gloss. These characteristics, despite its noxious fumes and high flammability, have made it the most widely used finish in refinishing shops and furniture factories since the 1930's.
It is common practice to change the color of a wood or wood-grained article after it has been finished or already used. Even if the finish is undamaged, effecting a color change generally involves stripping the article down to bare wood, and beginning the finishing process anew. For an article originally finished with nitrocellulose lacquer, this involves either physical stripping operations, or chemical stripping that generally includes the use of organic solvents, for example, acetone or methylene chloride.
After the article has been stripped of its original finish, the desired color change is usually effected by dyeing the article with a water, oil, or alcohol based aniline dye. These dyes are absorbed by the wood fibers, and if water-based, may raise the grain of the wood, necessitating a further sanding operation. Aniline dyes have the disadvantage that they commonly fade on exposure to light. After dyeing, the article is finished, and optionally sealed, using any of a variety of compatible sealers and finishes known to those skilled in the art.
Effecting a color change in a finished article of wood thus currently requires the tedious, time-consuming, and hazardous operations of stripping off the existing nitrocellulose finish, dyeing the wood, and applying a new coating. The equipment used in the stripping and recoloring operations must also be cleaned with an organic-based solvent, generating more hazardous waste that must be disposed. The organic solvents are now typically disposed of in publicly-owned treatment facilities or in industrial pretreatment facilities, increasing the burden on the water purification systems. The refinishing process often takes place at a refinishing plant or other site remote from the typical location of the furniture, because of the fumes and dust generated in the process.
it would be desirable to have a method to change the color of finished wood or a wood-grained article that does not involve the use of hazardous organic solvents, and thus the generation of organic fumes and that can be carried out without moving the furniture to a remote location. It would also be of benefit to have a method for effecting a color change in wood, or a wood-grained article in particular, that has been finished with a nitrocellulose lacquer that does not require the step of chemical or physical stripping of the original finish. It would further be very useful to have a method for effecting a color change in wood or a wood-grained article in which the original wood grain remains visible through the newly applied color layer.
It is therefore an object of the present invention to provide a means for effecting a color change in wood or a woodgrained article.
It is a further object of the present invention to provide a means for effecting a color change in an article of wood without stripping off an original nitrocellulose finish.
It is another object of the present invention to provide a means for effecting a color change in wood or a wood-grained article in which the original wood grain remains visible through the newly applied color layer.
It is a further object of the present invention to provide a means for converting an original finish to a pickled, or white-wash, finish.
It is another object of the present invention to provide a means for refinishing wood or a wood-grained article that does not require the use of organic solvents.